ICS1893 datasheet(71/152 Pages) ICST

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Chapter 8

Management Register Set

ICS1893 Rev C 6/6/00

June, 2000

ICS1893 - Release

8.3.11

Link Status (bit 1.2)

The purpose of this bit 1.2 (which is also accessible through the QuickPoll Detailed Status Register, bit

17.0) is to determine if an established link is dropped, even momentarily. To indicate a link that is:

• Valid, the ICS1893 sets bit 1.2 to logic one.

• Invalid, the ICS1893 clears bit 1.2 to logic zero.

This bit is a latching low (LL) bit that the Link Monitor function controls. (For more information on latching

high and latching low bits, see Section 8.1.4.1, “Latching High Bits”and Section 8.1.4.2, “Latching Low

Bits”.) The Link Monitor function continually observes the data received by either its 10Base-T or

100Base-TX Twisted-Pair Receivers to determine the link status and stores the results in the Link Status

bit.

The criterion the Link Monitor uses to determine if a link is valid or invalid depends on the following:

• Type of link

• Present link state (valid or invalid)

• Presence of any link errors

• Auto-negotiation process

For more information on the Link Monitor Function (relative to the Link Status bit), see Section 7.5.5,

“10Base-T Operation: Link Monitor”.

8.3.12

Jabber Detect (bit 1.1)

The purpose of this bit is to allow an STA to determine if the ICS1893 detects a Jabber condition as defined

in the ISO/IEC specification.The ICS1893 Jabber Detection function is controlled by the Jabber Inhibit bit in

the 10Base-T Operations register (bit 18.5). To detect a Jabber condition, first the ICS1893 Jabber

Detection function must be enabled. When bit 18.5 is logic:

• Zero, the ICS1893 disables Jabber Detection and sets the Jabber Detect bit to logic zero.

• One, the ICS1893 enables Jabber Detection and sets the Jabber Detect bit to logic one upon detection

of a Jabber condition. When no Jabber condition is detected, the Jabber Detect bit is not altered.

Note:

The Jabber Detect bit is accessible through both the Status register (as bit 1.1) and the QuickPoll

Detailed Status Register (as bit 17.2). A read of either register clears the Jabber Detect bit.

The Jabber Detect bit is a latching high (LH) bit. (For more information on latching high and latching low

bits, see Section 8.1.4.1, “Latching High Bits”and Section 8.1.4.2, “Latching Low Bits”.)

8.3.13

Extended Capability (bit 1.0)

The STA reads bit 1.0 to determine if the ICS1893 has an extended register set. In the ICS1893 this bit is

always logic one, indicating that it has extended registers.

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